Field of the Invention
The present invention relates to an information processing technique capable of recognizing a multi-touch operation input by a user.
Description of the Related Art
It is conventionally known that a touch input device is capable of acquiring X and Y coordinate values of each touched position on a screen, as input values, in response to a screen touch with a user's finger or a stylus, and performing various types of processing based on the input values.
Further, there is a conventionally-known technique generally referred to as a multi-touch operation, which enables a user to perform an intended operation by touching a plurality of points on a screen. In general, a representative multi-touch operation on a touch panel is a pinch operation, which is a user's operation that decreases or increases the distance between two points touched by a user on the touch panel. In particular, a user's operation that moves two touch points in such a way as to reduce the distance between these points is referred to as “pinch in”, which can realize a reduction of a displayed image. On the other hand, a user's operation that increases the distance between two points is referred to as “pinch out”, which can realize an enlargement of a displayed image.
As discussed in Japanese Patent Application Laid-Open No. 2011-059952, when a user moves at least one of two fingers contacting a screen, it is feasible to recognize a pinch operation according to a change in distance between two fingers and change the magnification ratio of a displayed image. Further, at the same time, it is feasible to scroll the displayed image according to a finger movement direction.